1. Field of the Invention
This invention relates to a thin reinforced nonwoven fabric comprising a liquid impervious polymeric layer, a compressed web of crimped fiber, a binder, and a reinforcing scrim. The fabric bulks when exposed to heat or flame and is useful as a component for fire blocking mattresses, upholstery, and the like. This invention further relates to a fire-blocked article incorporating this fabric. This invention also relates to processes for making this reinforced nonwoven fabric and incorporating the fabric into an article.
2. Description of Related Art
The State of California has led the drive to regulate and reduce the flammability of mattresses and mattress sets in an attempt to reduce the number of lives lost in household, hotel, and institutional fires. In particular, the Bureau of Home Furnishings and Thermal Insulation of the Department of Consumer Affairs of the State of California issued Technical Bulletin 603 “Requirements and Test Procedure for Resistance of a Residential Mattress/Box Spring Set to a Large Open-Flame” to quantify the flammability performance of mattress sets. In many cases, mattress makers want to include a layer of fire blocking, however, they do not want that additional layer to detract from the existing aesthetics of their mattresses.
Strong thin fabrics, such as a combination of staple fibers and a thin reinforcing scrim fabric, could be desired in many instances because they are durable and also are not likely to be objectionable. Various methods are known in the art for combining staple fibers and scrim fabrics that lock the staple fibers in place. One such process is hydro-entangling, also known in various publications as hydrolacing, spunlacing, and water-jet treatments, where high pressure water jets impact the staple fibers and drive them into the scrim, consolidating the fiber and scrim together. Another process known in the art for combining staple fibers and scrim fabrics is by needlepunching. In this process, barbed needles grab the staple fibers and drive them into the scrim, or into the internal fiber batting, locking together the structure. Nonwoven sheets made by these processes mechanically and strongly entangle the staple fibers either with themselves or with the scrim or both, limiting the ability of the fabric to bulk when heated or exposed to flame.
Still another process known in the art for combining staple fibers and scrim fabric is by adhesive lamination or the addition of binders. In this process, a binder or adhesive is used to either adhere or bind layers or individual fibers together. For example, U.S. Pat. Nos. 6,579,396 and 6,383,623 to Erb and European Patent EP 622 332 to Yamaguchi et al. both disclose the use of a binder to maintain the loft or thickness of these thick fabrics; that is, the nonwoven remains in a lofted or bulked form so that it will have resiliency.
In addition to the desire for strong thin fabrics as fire blockers, in many instances, there is a desire to protect the internals of a mattress or other upholstered article from bodily fluids or other aqueous liquids. What is needed therefore, is a thin reinforced fabric that can function as both a fire blocker and as a liquid barrier.